effective reduction in production cost. Therefore, the first concept study got an immovable lens tube. The original movable sliding tube was one of the most expensive parts, because it had to be precisely manufactured on a lathe for a light tight fitting. The second concept study retained the sliding tube for the lens, but used a selenium light meter. A light meter for the accessory shoe was assigned to be built by Gossen in early 1968, but finally an uncoupled light meter was integrated in the camera housing. The camera received the designation Rollei B 35, with the "B" indicating the light meter (German: Belichtungsmesser), a slightly cheaper model, omitting the light meter, was called Rollei C 35 for compact camera. The innards of the camera were simplified by using more plastic parts. The control wheels on the camera body were replaced by a more conventional aperture control at the lens tube, and the control wheel for exposure time was placed at the sliding tube base on the body. These changes resulted in the fully inserted lens protruded a bit more from the camera body than in the previous model. Both of these models offered a shutter timing range from 1/30 sec to 1/500 sec and an aperture range from f/3.5 to f/22. The focusing range reached from 3 feet (0.9m) to infinity. Two pairs of dots on the lens barrel indicate the depth-of-field for f/8 and f/16. The so-called Zeiss formula was inspired by this camera. Especially for the North American market, a special edition with an artificial leather covering in traffic-red, yellow-orange, deer-brown, steel-blue and white was produced, counting 100 items for each color; however, as these test samples did not cause much interest, they were not quoted in any price list. Rollei 35 B In 1976 the Rollei B 35 was renamed as Rollei 35 B without any further modification, to better conform to the Rollei designation scheme. Rollei 35 LED Without its own development department, the Singapore production facility asked Rollei Germany for permission to make a redesign of the Rollei 35 B. The uncoupled selenium light meter was replaced by a new electronically coupled light meter, using variable resistors for transferring the aperture and shutter control settings to the light meter. The new designation Rollei 35 LED resulted from the three light emitting diodes in the viewfinder, which indicated overexposure, correct exposure, or underexposure. In